Experimental and numerical determination of fluid velocity profiles and turbulence intensity in mixing vessels

In this study, both a laser-Doppler velocimeter (LDV) and a computational fluid dynamic (CFD) software package (FL UENI) were used to experimentally determine and numerically predict the velocity distribution of an unbaffled and a baffled mixing vessel. Two types of impellers were employed, namely a flat blade turbine (FBT) and a pitched blade turbine (PBT). These impellers were studied in a single-impeller or multiple-impeller configuration in the unbaffled and baffled vessels. The flow characteristics in the impeller regions were measured by LDV and used as boundary conditions in the numerical computation. Turbulence effects were numerically simulated using either the k-c or the algebraic stress model (ASM). In general, good agreement between the CFD predictions and the LDV measurements was obtained. Predictions in which the boundary conditions were specified at multiple surfaces in the impeller region (i.e., two planes instead of one) were found to be superior to those in which less accurate boundary conditions were used. The predictions based on ASM were typically found to be in closer agreement with the experimental data than those based on the k-c model. The flow patterns in the unbaffled vessels were found to be dominated by the tangential component of the velocity, regardless the types of impeller used. In the baffled vessels the flow patterns were strongly dominated by both the axial and tangentialcomponents. The presence of a second impeller in the baffled vessels altered the flow considerably, producing a strong vertical recirculation pattern between the impellers, and significantly reducing the circulation flow below the lower impeller

Physical mechanism of superluminal traversal time: interference between multiple finite wave packets

The mechanism of superluminal traversal time through a potential well or potential barrier is investigated from the viewpoint of interference between multiple finite wave packets, due to the multiple reflections inside the well or barrier. In the case of potential-well traveling that is classically allowed, each of the successively transmitted constituents is delayed by a subluminal time. When the thickness of the well is much smaller in comparision with a characteristic length of the incident wave packet, the reshaped wave packet in transmission maintains the profile of the incident wave packet. In the case of potential-barrier tunneling that is classically forbidden, though each of the successively transmitted constituents is delayed by a time that is independent of the barrier thickness, the interference between multiple transmitted constituents explains the barrier-thickness dependence of the traversal time for thin barriers and its barrier-thickness independence for thick barriers. This manifests the nature of Hartman effect.Comment: 9 pages, 3 figures, Some comments and suggestions are appreciate

Relationship between Crude Oil Prices and Stock Prices of Alternative Energy Companies with Recent Evidence

This paper examines the recent interactive relationships between crude oil prices and stock performances of alternative energy companies. Oil prices and stock index of alternative energy sector are found independent from each other before late 2006. Contrary to existing studies, however, we find significant interdependence between oil prices and stock index of alternative energy industry in the recent years. Since late 2006, oil prices become significantly responsible for the stock performances of alternative energy companies. This finding suggests that the stock market investors of alternative energy sector incorporate oil price shocks into their trading decisions only recently.Crude oil price; Alternative energy; Oil stock index

Hourly water level prediction of sungai bedup catchement using pre-developed ANNs model from Siniawan catchment

This study proposes the application of Artificial Neural Network in the prediction of water level under tidal influence for Sadong Basin. An Artificial Neural Network is undoubtedly a robust tool for forecasting various non-linear hydrologic processes, including the water level prediction. It is a flexible mathematical structure which is capable to generalize patterns in imprecise or noisy and ambiguous input and output data sets. In this study, the ANNs were developed specifically to forecast the hourly water level for Sg. Bedup Station. Distinctive networks were trained and tested using hourly data obtained from the DID Department in Kuching. The performances of the ANNs were evaluated based on the coefficient of efficiency, E2 and the coefficient of correlation, R. The back propagation algorithm was adopted for this study. The models used in this study is the network trained with scaled conjugate gradient algorithm (trainscg) with two hours of antecedent data, learning rate and the number of neurons in the hidden layer of 0.8 and 40 respectively. In this study, the models generated the R value for testing of 1.00 when it trained. It has been found that the ANN has the potential to solve the problems of water level prediction. After appropriate trainings, they are able to generate satisfactory results during both of the training and testing phases. Further, the strength and limitations of ANNs had been discussed, based on the resulted obtained in this study

Implementation of Data Synchronization Mechanism in Virtual Desktop Infrastructure

There are more and more applications and services of Cloud technology. Whether the government, enterprises or organizations, even everyone may have requirements of constructing cloud systems. To build the virtual cloud infrastructure VMware vSphere which is the leader of the information industry on virtual platforms can let users use Virtual Desktop Infrastructure by their mobile device. This study integrated some management programs such as Activity Directory, VMware vCenter, View connection server, VMware vSphere and used the shared storage system of FreeNAS to provide the cloud virtual environment to users. With the simple interface to manage, it successfully provides administrators to build Virtual Desktop Infrastructure faster. Users can use their own device to control the virtual desktop in a mobile classroom by VMware Horizon View or browser. Users can also use a shared storage system to be the information exchange platform. If you can connect to the Internet, you can use your own virtual desktop anywhere. Finally, the complete construction implements the combination of several operating systems and improves their performance to save lots of hardware cost. It also meets the social focus of carbon reduction and environment protection to achieve sustainable use

A Community-Based Walk-In Screening of Depression in Taiwan

Depression is a crucial public health problem because of its relatively high association with suicidal attempts, prolonged social isolation, poor physical health, and dementia. However, the available data and study on the prevalence of depression in Taiwan were mostly completed within the previous 1 to 2 decades, and these studies were limited to certain areas or populations. Little is known regarding the current status of depression in Taiwan. We used a brief tool, the Center for Epidemiological Studies Depression Scale (CES-D), to screen depression in 4 areas among the general and aged population. The results showed a higher CES-D score in the southern area among general (mean ± SD: 7.8 ± 8.4) or aged participants (mean ± SD: 7.2 ± 8.0) compared with other areas. The ratio of suspected depression patients was 16.4% of all recruited participants and 13.3% of aged participants. These results may provide information for this public health issue

Albumin fibrillization induces apoptosis via integrin/FAK/Akt pathway

[[abstract]]Background: Numerous proteins can be converted to amyloid-like fibrils to increase cytotoxicity and induce apoptosis, but the methods generally require a high concentration of protein, vigorous shaking, or fibril seed. As well, the detailed mechanism of the cytotoxic effects is not well characterized. In this study, we have developed a novel process to convert native proteins into the fibrillar form. We used globular bovine serum albumin (BSA) as a model protein to verify the properties of the fibrillar protein, investigated its cellular effects and studied the signaling cascade induced by the fibrillar protein. Results: We induced BSA, a non-cytotoxic globular protein, to become fibril by a novel process involving Superdex-200 column chromatography in the presence of anionic or zwittergenic detergent(s). The column pore size was more important than column matrix composite in fibril formation. The fibrillar BSA induced apoptosis in BHK-21 cell as well as breast cancer cell line T47D. Pre-treating cells with anti-integrin antibodies blocked the apoptotic effect. Fibrillar BSA, but not globular BSA, bound to integrin, dephosphorylated focal adhesion kinase (FAK), Akt and glycogen synthase kinase-3β (GSK-3β). Conclusion: We report on a novel process for converting globular proteins into fibrillar form to cause apoptosis by modulating the integrin/FAK/Akt/GSK-3β/caspase-3 signaling pathway. Our findings may be useful for understanding the pathogenesis of amyloid-like fibrils and applicable for the development of better therapeutic agents that target the underlying mechanism(s) of the etiologic agents. ? 2009 Huang et al; licensee BioMed Central Ltd

Could the North Pacific Oscillation be modified by the initiation of the East Asian winter monsoon?

Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 33(6), (2020): 2389-2406, doi:10.1175/JCLI-D-19-0112.1.This study investigates the modulation of North Pacific Oscillation (NPO) variability upon initiation of the East Asian winter monsoon (EAWM). The data show that the initiation of EAWM in the Philippine Sea strongly connects to the southern lobe variability of the NPO in January followed by a basin-scale oceanic Victoria mode pattern. No apparent connection was found for the northern lobe of the NPO when the ENSO signals are removed. The strengthening of the EAWM in November interacts with the Kuroshio front and generates a low-level heating source in the Philippine Sea. Significant Rossby wave sources are then formed in the lower to midtroposphere. Wave ray tracing analyses confirm the atmospheric teleconnection established by the Rossby wave propagation in the mid- to upper troposphere. Analyses of the origin of wave trajectories from the Philippine Sea show a clear eastward propagating pathway that affects the southern lobe of the NPO from the southern lobe of the western Pacific pattern at 500 hPa and above on the time scale of 20 days. No ray trajectories from the lower troposphere can propagate eastward to influence the central-eastern subtropical Pacific. The wave propagation process is further supported by the coupled model experiments.We thank three anonymous reviewers for their constructive comments that have helped to improve the clarity of the presentation. This study was supported by the MOST Grants 107-2611-M-002-013-MY4 and 108-2111-M-002-006 -MY3, Taiwan.2020-08-2

Model-Based Estimation With Boundary Side Information or Boundary Regularization

The authors have previously developed a model-based strategy for joint estimation of myocardial perfusion and boundaries using ECT (emission computed tomography). They have also reported difficulties with boundary estimation in low contrast and low count rate situations. Here they propose using boundary side information (obtainable from high resolution MRI and CT images) or boundary regularization to improve both perfusion and boundary estimation in these situations. To fuse boundary side information into the emission measurements, the authors formulate a joint log-likelihood function to include auxiliary boundary measurements as well as ECT projection measurements. In addition, they introduce registration parameters to align auxiliary boundary measurements with ECT measurements and jointly estimate these parameters with other parameters of interest from the composite measurements. In simulated PET O-15 water myocardial perfusion studies using a simplified model, the authors show that the joint estimation improves perfusion estimation performance and gives boundary alignment accuracy of <0.5 mm even at 0.2 million counts. They implement boundary regularization through formulating a penalized log-likelihood function. They also demonstrate in simulations that simultaneous regularization of the epicardial boundary and myocardial thickness gives comparable perfusion estimation accuracy with the use of boundary side information.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85825/1/Fessler106.pd